The play of an instinct may therefore be analyzed into four processes. They succeed one another as sensation—endocrine stimulation—tension within the vegetative system—conduct to relieve tension. The dash is the symbol of a cause and effect relationship.
This equation for an instinct, based upon an analysis of the working of the sex instinct, is the model for the analysis of all instincts, and therefore of all the compounded instincts that all human behaviour may be resolved into. Conduct, that fascinator of the common gossip and the great novelist alike, normal and abnormal, social and asocial, in all their complexities, even unto the third and fourth generation, the Freudian complexes, is governed therefore by the same laws that determine the movements of the stars and the eruptions of volcanoes. The most interesting factor in the instinct equation is the endocrine, because that is the one that is most purely chemical.
ENDOCRINE CHARGING OF WISHES
It is the distinction of modern psychology that it has established the wish (craving, need, desire, libido) as the moving force in any psychic process. The position of the wish in psychology as the force within and behind the instinct may be compared to that of energy in physics, when it was elevated to a central position in the explanation of physical processes in the nineteenth century. The concept of the charged wish has illuminated all the hidden recesses and rendered audible all the subdued murmurings of the mind. The truly novel in the content of the idea is the recognition of the fact that the wish is charged. Now it could never be charged in a vacuum. That means that a wish could never be born in the brain alone. For the brain has no power to charge itself with energy—it can only store and transmit. If a wish is potential energy that must be transformed into kinetic, it must have a source. That source is the vegetative system. Without the vegetative system, the great complex of viscera in the abdomen and chest, blood and its vessels, endocrines, muscles and nerves, the brain would remain but an intricate cold storage plant of memories, associations of past experiences. It would need no change and initiate no effort. But when the wish enters upon the scene, it is as if a dead storage battery has been refreshed with new current. Enriched with billions of electrons there is a stir and a movement, dynamic mind. But the dynamo is the more ancient possession of the animal, the vegetative apparatus. In short, what must always be remembered is that a wish is never cerebral, but always sub-cerebral, visceral, in its origins.
The sub-cerebral makes the cerebral. Activities in the nervous system below the brain and especially the vegetative system, force upon it its function of the active verb. It has to be, to do, and to suffer, and then to manipulate the environment to satiate the insatiable viscera, insatiable because the local chemistry is continually raising the tension of one or the other of them. A physics of human behaviour becomes possible with the aid of these concepts of endocrine regulation of intravisceral pressure, and intervisceral equilibrium, an intramuscular pressure and an intermuscular equilibrium, with the brain as the shifting fulcrum of the system.
The sensation of hunger, as we have seen, serves as good an exemplar as any of this mechanism of the wish. Hunger is preceded and accompanied by contractions of the stomach of increasing intensity. Those contractions must be brought about by a substance acting upon the nerve endings in the wall of the stomach. As it closes down upon itself, waves pass up and down. With each wave, the pressure within it rises. The exact amount of the pressure may be accurately measured by means of a small balloon swallowed and then inflated. When the pressure rises above a certain figure, the sensation of hunger breaks into the consciousness of the individual. We infer that certain sensory impulses sent up to the brain attain a strength that finally forces itself into the conscious field of feeling. The sensation of hunger varies from individual to individual because of variation in the reaction throughout the vegetative system. Most often it is a sense of movement or even an itch in the upper abdomen. Let some cause produce a weakening or cessation of the movements of the stomach—as fear and anger—and the sensation of hunger disappears coincidently with the drop in the pressure within it. As the mathematicians would say, the wish is a function of the pressure, and so of the concentration of substance behind the pressure.
We have in hunger the wish reduced to the lowest terms, the most primitive form of it. Yet we may resolve all wishes, even the most idealistic, into the same terms. As the vegetative system becomes habituated by repeated experience to react in the same way to the same stimulus, permutations and combinations of wishes become possible until at length the inscrutable complexities of the behaviour of civilized man are evolved. We have to thank Von Bechterew, the greatest of Russian physiologists, for these fundamental principles, so important for the understanding of the control of human life and conduct.
The associated reflex, aboriginal ancestor of the involved train of associations that constitute the highest thought, conduct and character, is the unit of the system. Recall the classic example cited. If a piece of meat is shown to a dog, his mouth waters. If now you proceed to ring a bell before offering the meat, his mouth will water only when he sees or smells the meat. If, however, the ringing of the bell precedes the meat a sufficient number of reactions, a time comes when merely the sound of the bell will cause salivation, without the presence of the meat. So it is with the associated reactions of the internal secretions. A stimulus originally indifferent to the endocrines may, by association, the laws of which are many, come to act like a spark to the endocrine-instinct mechanism. Hence we can account for the subtle play of instinct throughout all thinking.
Even objects resembling the specific excitant of an instinct only remotely, or in some one quality, may start its mechanism and a host of associations bound up with it. Thus the maternal instinct may be excited by the sight of a baby. But because a baby is small and delicate, anything small and fine, a tiny book, a toy, a miniature, may arouse it. The object is then said to be appealing. The doctrine of association of instinctive and so of endocrine reactions enables us to understand the feeling—tone that at any moment pervades consciousness as well as its content.
Choices, the psychology of selection of food, color, friends, mates, amusements also become explicable rationally. For conflicts among the different components of the vegetative system are continuous and inevitable. If the pressure within a viscus has been heightened, and persists, that is, is not disturbed by some other associated factor or instinct, conduct results to lower the pressure to what it was before the instigator of the tension appeared. But if another instinct is sparked, or another associated factor comes into play, another focus of increased pressure within the vegetative system is created, with another stream of energy flowing to the brain and demanding an outlet. This clash of instincts, the struggle between different foci of the vegetative system competing for the possession of the brain, is a common everyday process in conduct. Which will win means which will will. And so we have an energetic basis for volition.